To begin with what style of casting would you like to do? If you were looking for a good all around line, where you can do spey and overhand, I would get a Windcutter 5/6. For skagit what I would go with a 300gr. get the #7 skagit tip and pick up a 15′ type 3 anda 15′ type 6 sink tip which are 84gr. Cut the sink tips back a little I think right around 13′ would be good. This way you can fish any situation that may present itself. Hope this helps.
I just picked up a Beulah 10’6″ 8 wt. switch rod this fall, also a med-fast. I have the 400 grain rio skagit on there now, and it turns over very well at short to medium ranges. Haven’t had to cast much farther than 50 ft. as of yet. I am a novice to spey but haven’t had any trouble casting with this setup.
As was mentioned before, other lines are probably better suited for multi-app use. Check out Beulah’s elixr series.